An improved progressive damage model for three-dimensional five-directional braided composites under longitudinal compression

Various failure modes of three-dimensional five-directional braided composites (3D5DBCs) under longitudinal compression have been observed, including yarn fracture and kinking, transverse inter-fiber cracking, matrix plastic deformation/fracture and fiber/matrix interfacial debonding, leading to the difficulty in predicting their mechanical properties. This study proposes an improved progressive damage model for 3D5DBCs under longitudinal compression, addressing all the observed failure modes. Then, the proposed progressive damage model is implemented in a finite element (FE) model to predict the mechanical responses and properties of 3D5DBCs under longitudinal compression. The numerical predictions in terms of compressive stress-strain relations, compressive strengths and failure modes are in good agreement with the experimental results, demonstrating the effectiveness of the proposed progressive damage model. Finally, the failure envelopes of 3D5DBCs under compression-shear loading are predicted using our FE model, and the effectiveness of several classical failure criteria on the strength prediction of 3D5DBCs is discussed.